Psoriasis is a chronic, hereditary, recurrent, papulosquamous dermatosis, the distinctive lesion of which is a vivid red macule, papule, or plaque covered almost to its edge by silvery lamellated scales. It usually involves the scalp and extensor surfaces of the limbs, especially the elbows, knees and shins.
Traditional treatments of psoriasis have included daily or more frequent application of corticosteroids such as betamethasone acetate, betamethasone valerate, fluocinolone acetonide, fluocinolone acetonide acetate, and the like dissolved or suspended in an ointment, lotion, or glycol solvent to the affected area. Occlusive techniques such as wrapping cortiocoid treated areas with a moisture-impermeable wrapping such as a self-attracting plastic film such as polyvinylidene chloride film (SARAN) has been found to increase the effectiveness of the treatment. Penetrating solvents have been investigated for enhancing percutaneous absorption of these drugs in an effort to more successfully treat more resistive conditions.